I wanted something that I could backpack and also ride my bike. I settled on the Sevlor K5. It seemed like a pretty good compromise. At 26 lbs it is not too heavy and the reviews were mostly positive.
It cost about $250, quite a bit cheaper that some of hardshell collapsable kayaks.
The backpack, unfortunately, is not really designed for long hauls. There is no frame and the hip belt rides high so it is basically a rucksack. With water, food, etc. the pack ends up weighing north of 30lbs which is on the heavy side for a rucksack. I modified the hip belt by attaching a more comfortable belt from an old pack. Even with this modification, hiking for more than 5 or 6 miles would be rough.
The kayak is great. It does not track as well as a standard kayak and rides a bit higher but it is perfectly adequate. And it is a really cool design. The pack turns into a quite comfortable seat. The included paddle is a bit cheap but works alright if you are careful with it. The pump is very light and pumps on both strokes so the three kayak chambers are quickly filled.
I quickly realized that if I wanted to get the kayak more than 5-6 miles from home I would need to use my bike. Riding with the kayak on my back works but I still need to hump the kayak back to the bike after kayaking. I wanted to essentially add wheels to the kayak so I could pull it with my bike or push it when hiking. I found a bike trailer I thought would work, the Sepnine Bike Cargo Trailer.
The trailer is 11.5 lbs and collapses so I can put it on my kayak when I reach my put-in spot.